1. Field of the Invention
This invention relates generally to apparatus used in conjunction with a respiratory support system. More specifically, the present invention relates to a method and apparatus for the attachment of accessory devices to a respiratory support system. Even more specifically, the present invention relates to a ventilator manifold for use with a respiratory support system which accommodates the attachment and detachment of accessory access devices therewith without interruption or loss of continuous respiratory support of a patient.
2. Prior Art
Respiratory support systems used for the ventilation of critically ill patients are now commonly used in medical facilities. Typically, a prior art respiratory support system includes a tracheal tube positioned either directly, or through the nose or mouth, into the trachea of a patient, a manifold connected to the tracheal tube at one port position thereof, and a source of breathable gas connected at a second port thereof. The purpose of the respiratory support system is to assist the patient in maintaining adequate blood oxygenation levels without overtaxing the patient's heart and lungs.
While a patient is attached to the respiratory support system, it is periodically necessary to aspirate fluid from the patient's trachea or lungs. In the past, in order to accomplish aspiration, it has been necessary to disassemble part of the respiratory support system, either by removing the ventilator manifold therefrom or by opening a port of the manifold and inserting a small diameter suction tube down the tracheal tube and into the patient's trachea and lungs. The fluid was then suctioned from the patient and the suction catheter was removed and the respiratory support system reassembled. However, due to the interruption of respiratory support during this procedure, a patient's blood oxygen often dropped to an unacceptably low level, even when other previously known breathing assistance efforts were simultaneously provided.
One solution to the above problem, which is generally exemplary of the prior art, is shown in U.S. Pat. No. 5,073,164 to Hollister et al., which includes a ventilator manifold having an access port therethrough which is adapted to receive a connector of the suction catheter device. The suction catheter device positions a catheter within the ventilator manifold without substantial manifold pressure loss. The suction catheter device includes an envelope which is positioned around the catheter portion thereof in order to prevent contamination of catheter surfaces intended to be inserted into the patient's trachea and lungs.
Although this type of ventilator manifold and suction catheter device connection allows continuous respiratory support of the patient during suctioning of fluid from the patient, it nevertheless has several drawbacks associated with its use. For example, removal of the suction catheter device from the manifold, such as for the purpose of replacing the suction catheter device, or for attaching another accessory to the manifold (e.g., a manual resuscitation bag or a metered dose inhaler) cannot be accomplished without loss of internal manifold pressure and thereby a compromise of the integrity of the respiratory system. Further, separation of Hollister et als'. suction catheter device from their suction control valve cannot be accomplished without opening the manifold to atmospheric pressure through the catheter. Therefore, replacement of either the suction catheter device or the suction control valve is not possible without loss of internal manifold pressure. Instead, respiratory support of the patient is compromised whenever the suction catheter device or the suction control valve is removed from the system for any reason. Since the suction catheter device tends to become contaminated relatively quickly with respect to the suction control valve and the ventilator manifold, it must be changed out of the system and replaced on a relatively frequent basis. However, because of the problems caused by loss of respiratory support during replacement, the ventilator manifold and/or the suction control valve are often prematurely discarded along with the suction catheter device in order to limit replacement time and the number of replacement procedures required.
U.S. Pat. No. 4,351,328 to Bodai attempts to solve one of the above problems by forming an opening in the ventilator manifold which is blocked by a pre-punctured resilient seal through which a catheter can be passed without substantially effecting the integrity of the system, i.e., without substantial gas exchange or pressure loss between the interior of the manifold and the atmosphere.
The Bodai device, although allowing entry and removal of a suction catheter through the ventilator manifold during continuous respiratory support of a patient, nevertheless fails to completely resolve the existing problems in the prior art. Specifically, the pre-punctured resilient material in Bodai's manifold opening allows only for the insertion of a catheter therethrough, and fails to accommodate a suction catheter device which includes a collapsible envelope which surrounds and seals the catheter against exterior surface contamination. Because of this, the suction catheter must be replaced after each use. Further, there is no design consideration for the attachment of other accessory devices to the manifold, such as a manual resuscitation bag or a metered dose inhaler, which are often necessary for use in the care of a patient.
Also, the system described by Bodai tends to cause mucus and other fluids from the patient's lungs and trachea to collect in the manifold as the catheter is pulled past the pre-punctured resilient seal when being withdrawn. Because of this contamination problem, it is often necessary to replace the manifold on a more frequent basis than would otherwise be necessary, which necessitates a pressure breach in the support system.
There therefore exists a need in the art for a respiratory support system which includes a ventilator manifold which allows simple attachment and detachment of an accessory access device therefrom during continuous patient respiratory support, without substantial pressure loss from the manifold and without substantial collection of body fluids in the manifold.